1. Field of the Invention
The present invention relates to a prosthetic foot, and more particularly to a prosthetic foot being adjustable in heel and keel spring capacities for complete customization and personalization, being adjustably vertically connectable at the ankle joint, and having a rigid angle joint.
2. Description of the Related Art
People frequently are in need of prosthetic limbs as a result of accidents, disease or birth defects. The need for quality prosthetic feet is high. There have been many attempts to make suitable prosthetic feet, each desiring to reach goals of safety, functionality and comfort, among other qualities. The existing prosthetic feet have achieved varying levels of success at attaining each of these stated goals. Further, many strategies have been utilized in designing prosthetic feet. Some designs are relatively noncomplicated, and seek to use a simple design. Other designs are complex, and seek to simulate or copy the structure of the human foot.
One prosthetic foot in particular is made by Freedom Innovations and is sold under the name Renegade LP. This foot has an uninterrupted component spanning from the ankle to the toe. A second component extends from the heel to the front of the foot. While this foot may work well for its intended purpose, it is not without some limitations. For example, there is not a heel spring incorporated into the design. Another limitation of this foot is that there is no way to adjust the location of the heel with respect to the residual limb.
Another existing prosthetic foot is sold by Ossur under the name Modular III. This foot has one uninterrupted component forming the ankle and spanning to the toe area. A heel component depends rearward from the major component to the heel. This heel component connects to the bottom surface of the major component. A primary advantage of this foot resides in its simplicity. However, there are drawbacks also associated therewith. One limitation is the lack of adjustability of the location of the heel with respect to the residual limb. A further limitation of this foot is the lack of a heel spring.
A third prosthetic foot is shown in U.S. Pat. No. 5,695,527 to Allen. This patent shows a coil prosthetic foot formed by a continuous coil spring having a foot center coil section, a heel extension section and a forefoot extension section. One drawback of the design shown in this patent is that lack of adjustability of the amounts of flex in the heel extension section and the forefoot extension section. Also, no rigid center support is shown in this patent for allowing a strong and vertically adjustable connection to adjacent prosthetic components.
A further prosthetic foot is an assembly that is shown in U.S. Pat. No. 6,129,766 to Johnson et al. This patent discloses an ankle member, a heel member pivotally connected to the ankle member, and an elongate metatarsal-toe member having a rear portion underlying a forward portion of the heel member and projecting forwardly from the heel member. This foot has compressible elements incorporated between the pivotally connected members. This foot, being an assembly, is relatively complicated when compared to the previously described prosthetic feet. A further limitation of this foot is that there may be inherent noise problems incorporated into the design of the compressible elements. This is evidenced by the presence of, and the need for, noise abatement features being described in the disclosure.
A still further prosthetic foot is sold by Otto Bock under the name LuXon Max. This foot shows a relatively flat and uninterrupted component spanning from the ankle location forward to a location above and rearward of the toe location. Distinct heel and toe components are connected to the bottom of the flat component. One limitation of this foot is that there is no way to adjust the location of the heel with respect to the residual limb. Another limitation of this foot is that there is no heel spring incorporated into the design. A gap or channel is apparent between the heel and toe components. The shown gap is open to the bottom of the foot, such that any flex in the foot will cause the size of the gap to expand or increase. Accordingly, there is no way to control the flexibility or adjust the rate of flexibility shown or taught in the LuXon Max foot.
Yet another prosthetic foot is shown in U.S. Pat. No. 6,602,295 to Doddroe et al. The foot shown in this patent has a foot plate, which is an uninterrupted plate spanning from heal to toe. A toe spring and a heel spring are provided. The toe spring is forward of the heel spring. The toe spring and heel spring are independently connected to a top plate. Further, the heel spring is rotatably connectable to the top plate and the foot plate.
Another prosthetic foot is shown in U.S. Pat. No. 6,241,776 to Christensen. The foot shown in this patent has a forefoot reinforcement member extending from an attachment section, through a curvilinear spring and arch section, to a toe end. A heel member extends from the arch section to the heel end. The strength and energy return in this foot is due to the flexing of the members. A limitation of this foot is that it is lacking is adjustability. A further limitation is that it does not have a heel spring.
Another prosthetic foot is shown in U.S. Pat. No. 5,037,444 to Phillips. That patent shows a foot with a forefoot portion and a demountably connected heel portion. At toe-off, the energy return is created from energy stored during the flexing of the forefoot member. One limitation is that the foot of this invention does not have a heel spring. A further limitation is the lack of adjustability of the location of the heel.
A still further prosthetic device is shown in U.S. Pat. No. 5,545,234 to Collier, Jr. This patent shows a modular foot with a heel section and an elongate midfoot section. The heel and midfoot sections are configured for detachable combination via a coupling joint. A foot with a differential stiffness characteristic is provided due to a heel section being formed of a material with a first predetermined stiffness characteristic and a midfoot section being formed from a material of a second predetermined stiffness characteristic. One drawback of materials with predetermined stiffness characteristic is the lack of adjustability.
Thus there exists a need for a prosthetic foot that solves these and other problems.